FARMYARD MANURE.

New Zealand Journal of Agriculture, Volume XXX, Issue 1, 20 January 1925, Page 35

FARMYARD MANURE.

ITS CONSERVATION AND UTILIZATION

W. J. McCulloch,

Instructor in Agriculture, Palmerston North.

The question which probably most exercises the mind of the average New Zealand farmer in regard to the use of farmyard . manure is, “ Does its fertilizing-value justify the expenditure of labour in conserving and subsequent utilization ? ” As the climatic conditions of this country do not demand that farm-animals should be housed continuously for lengthy periods each season, the quantity of manure collected at the average steading is relatively small. It is therefore very evident that the stock themselves are responsible for ' the distribution of the bulk of the manure, and in'this way contribute very largely to the fertility upkeep of our farm lands. Hence also the value of using the tripod harrows at short intervals on the lowcountry pastures. This is plainly the most economical method of handling animal-manures. In a consideration of the value of farmyard manure due allowance must be made for more than the actual commercial value of its fertilizing ingredients. It must be clear that the fertility of a soil is dependent upon more than the addition of so-called plant-foods. For instance, the humus content, which is one of the . most important factors in fertility upkeep, can be largely depleted by the production of annual crops which are almost entirely removed. In order to be quite clear, on the position one must first . recognize that there is a distinction between what' are'known as manures and those termed artificial fertilizers, the chief difference being in respect to the other important functions of, for example, farmyard manure. For while an organic manure supplies plant-food, it also aids in the general improvement of plant-foods already in the soil to 1 a very marked degree,'while the artificial fertilizer as a rule only furnishes plant-food. ' Another important factor of all fertile soils is texture, and here again farmyard ' manure exerts a very beneficial influence. The mechanical and physical benefits derived by soil from an addition of such manure are very important. The benefits extend alike to light and heavy soils. In light soils organic matter-frequently so deficient, and which no amount of artificial fertilizer can make up for—is. supplied by farmyard manure, .while at the same time the latter assists consolidation and retention of moisture. The advantages to heavy clay soils, although in a different direction, are no less marked. It makes their working much easier by opening the soil-mass to the beneficial influences of warmth, aeration, and oxidation. It will therefore be realized that farmyard manure is unique in its effect, and that it must be given credit for more than its’actual commercial value as a plantfood. ■ ■

The value of introducing and encouraging useful soil-bacteria . is now well understood, and as an efficient supply of organic matter in a soil is known to be necessary for the growth and well-being of these organisms we realize a further important part played by the addition of farmyard manure. The manurial value of crops fed off on the ground

is universally recognized, yet the fact of the value of properly conserving farmyard' manure continues, in many instances, to be neglected.

Much as we appreciate the value of an organic manure, it is often argued that the average New Zealand soils are not yet really, deficient in humus, and that the necessity for the proper care and use. of farmyard manure can quite easily be left in abeyance meantime. In answer to this statement it has to be remembered that the stables, cow-sheds, and yards must of necessity be kept ' cleared of manure,: but there can be no real reason why it should be dumped in untidy ‘heaps in odd corners and left lying at the mercy of heavy, washing rains, which remove in a liquid form to the nearest drain the most* quickly soluble and available plant-foods. Even if it has to be looked upon as a necessary evil it must be handled and, sooner or later, the accumulation carted , out and spread on - some field. There appears to be no valid reason why a little extra care should not be'taken to save the best of the material and utilize it as a fertilizer and soilimprover, while at the same time reducing annual expenditure on artificial fertilizers. . The ideal method would be to spread the manure daily and plough it in; but this may be prohibitive on account of the labour involved, so that storage under reasonably good conditions will be the more convenient method. Where this can be accomplished under cover the value of the manure is greatly enhanced but this may also be too expensive, so that the manure-heap in the open is likely to be more general. At the outset every attempt must be made to avoid drainage running from the heap, and if a concrete floor with shallow sides is out of the question, then a z shallow depression should be scooped out, and if the bottom consists of an impervious clay all the better, as the object is to conserve all liquid. If the subsoil is loose, then a few loads of clay puddled on the bottom of the depression will answer. Should the circumstances prevent the scooping-out of a depression, then a ridge of loose soil can be spread round the outskirts of the heap, and as the moisture becomes absorbed it can be thrown on top of the manure-heap and replaced by more. soil. In building the heap it should be kept evenly spread and level on top, consolidating the'mass as much as possible in order to avoid undue heating. Horse-manure will heat readily if air is not excluded, especially if combined with too much , straw. This causes a great loss of ammonia, and must be avoided as far as possible by .mixing with alternate layers of cow or pig manure, or by pumping liquid manure on to the heap. Where none of these methods is practicable, and overheating occurs, a layer of soil should be spread on top of the heap. The soil will absorb most of the ammonia, and by consolidating the heap assist to- prevent heating. - It has often been suggested that gypsum, superphosphate, or kainit should be used as preventives against loss of ammonia in stables, but though good results have occasionally followed their use it is now recognized that, all are open to objection, and they are not recommended. It is preferable to rely on straw or hay as a litter to absorb the moisture. As an indication of the loss sustained by uncovered manure-heaps compared with those kept under cover, a few .. experiment - station

results may be here quoted. Rothamsted reports that covered manure increased the) yield. of potatoes by 7 cwt., and that of 1 wheat by 5 bushels of grain and 4 cwt. of straw per acre. At Woking covered manure increased a wheat crop by 2 .bushels of grain and 2 cwt. of straw per acre. The College of Science for Ireland, experimenting with potatoes, dressed two plots with farmyard manure. at . the rate of 18 tons per acre, one from a covered and the other from an open heap. The yield from the former plot was 9 tons 14J cwt. per acre, while that from the latter was 7 tons 14I cwt. Every attempt should be made to save the liquid manure from the shed-drains. This manure should be drained into a tank or shallow concrete well placed . below ground-level, and in a convenient position so that it may be pumped to a tank on a dray and directly applied to the field—preferably grassland. If conditions permit ■ it may even be gravitated direct from the drains and used to irrigate •the pastures. Failing both these 'methods it should be pumped on to the manure-heap. On no account should liquid manure be allowed •to run to waste, as it contains a very appreciable amount of quickly available .plant-food — approximately two-thirds of the total nitrogenous matter and four-fifths of the total potash (the phosphoric acid being mostly contained in the solids). It has been found that 1,500 gallons of liquid manure are equivalent to. 150 lb. sulphate of ammonia and 4| cwt. of kainit. - As an addition .to light soils farmyard manure should 'be well rotted (not ' firefanged) or what is generally termed “ short.” ' On the •other hand, it should be long or strawy if for use on heavy or ■clayey soils. The straw which has been used as litter or bedding being more intact in the latter kind tends to keep the soil open, while in the former the well-rotted material brings about consolidation •of the soil-mass and assists in retaining moisture, &c. Farmyard manure should rather be distributed over as large an area as is ■consistent with practical convenience, and so long as the distribution is even and in combination with artificial fertilizers applied separately, it will be found without exception that much 1 better results will be •obtained than if larger amounts of either are used separately. Farmyard manure varies much-in composition, and although it is often •called a complete manure it is not really well balanced, being usually •deficient in phosphoric acid. For this reason it should be used in •conjunction with one of the artificial phosphatic fertilizers. As regards the time of year when farmyard manure should be applied, ’ much depends' on the’ circumstances. Where it is desirable to apply it to pastures it should be carted and spread during winter or early spring, and the field thoroughly tripod-harrowed- as soon as practicable afterwards. . For the growing of green fodders or roots it must be spread and ploughed in early, or some considerable time before sowing. Such crops as chou moellier, maize, thousand-headed kale, &c., being gross feeders, readily respond to an application of farmyard manure. In the case of the potato crop it can be spread between the ridges, together with. artificial fertilizer, and the tubers planted, after which the whole will be covered by splitting the drills in the -ordinary way.